Coupon Accepted Successfully!


Displacement and Velocity

Suppose two cars A and B start out simultaneously from O. Car A travels towards the north and car B towards the east. After 1 hour, both are at a distance of 50 km from O but their positions with respect to O are not the same. A is 50 km to the north of O and B is 50 km to the east of O.

So, we see that in order to completely specify the position of a moving object with respect to a reference point(in this case O), it is necessary not only to specify the distance of the moving body at any time from O, but its direction with respect to O also.

Displacement of a body from a fixed point is its distance from the point in a specified direction.



Similarly, if we say that a car moves with a speed of 50 km/h from O, we would not know whether we mean car A or car B as their motions with respect to O are quite different. In order to completely specify the motion of a moving body, it is not enough to state its speed only; we also need to specify the direction in which it is moving.

Velocity of a moving body is its speed in a specified direction, or its rate of change of displacement with time (displacement being with respect to a fixed point). Its unit is the same as that of speed. Displacement and velocity are vector quantities.

In case the velocity of the object is changing at a uniform rate, the average velocity is the arithmetic mean of the initial and final velocities. Hence, if ‘u’ is the initial velocity, ‘v’ will be its final velocity,
Average velocity vav = (u + v) / 2.

Test Your Skills Now!
Take a Quiz now
Reviewer Name